If the steering box is anything like the ones used on every other Mercedes, then yes, it can be adjusted. On top of the steering box is a 6mm allen head bolt with a 19mm hex locknut. Loosen the locknut. Turn the allen head bolt out - anti-clockwise.

To do this correctly, the tie rods must be disconnected and the torque required to turn the steering wheel measured. The torque increases near the on-center "dead ahead" position.

In practice, it works acceptably to adjust it 1/4 turn at a time until the result is satisfactory. It is very important not to overdo the adjustment - that will cause internal binding and eventual damage to the steering box. It is quite evident when the steering is too tight; the car drives poorly, does not track straight down the road, and the steering does not return to center without assistance from the driver.

Good luck,

- JimY